Drivers who smoke cannabis up to three hours before driving almost double the risk of being involved in a ‘serious crash’, according to a report published by the British Medical Journal (BMJ).
Researchers from Dalhousie University, Nova Scotia, Canada, found that the impact of cannabis consumption “on the risk of minor crashes remains unclear”, but they suspect it “could be a risk factor”.
The new study involved people who either tested positive for cannabis use through blood tests, or who said they had used cannabis in the previous three hours.
It is thought to be the first study looking at crashes involving drivers who have only taken cannabis; other studies have failed to separate out the effects of alcohol and other substances from cannabis use.
An overview of the report says: “The findings of the linked paper… add weight to the argument that cannabis users should be deterred from driving while intoxicated because of the risk of injury or death to themselves and others”.
Mike Penning, road safety minister, said “Drug driving is a menace which is why we are going to introduce a new drug-driving offence and drug-screening equipment to make it easier for the police to test for the presence of drugs and crack down on this irresponsible minority.
“We are also collecting information from coroners on the presence of drugs in drivers at autopsy to give us a better picture of the part drugs play in accidents on the roads.”